JPG Compressor

A JPG compressor that shows you exactly what you get

This JPG compressor re-encodes JPEG photos at the quality you choose and shows the result next to the original before you download anything. Drag the divider to look for blur or blocky artefacts, zoom in to check fine detail, and watch the file size change as you move the slider.

Because it is built only for JPEG, it reads the quantisation tables inside each photo to estimate the quality it was saved at, reports baseline or progressive encoding and the chroma subsampling, and lets you keep or remove EXIF. Everything runs in your browser — no upload, no account, no watermark.

How to use the JPG Compressor

1. Drop one or more JPG photos on the upload area, click it to choose files, or paste an image with Ctrl+V.
2. Move the JPEG quality slider. Sizes and the comparison view update as you drag; 70–85 is the usual sweet spot.
3. Optionally set a Max width or height — resizing a 4,000 px phone photo to 1,600 px saves more than any quality setting.
4. Leave Keep EXIF unticked to remove camera and GPS data, or tick it to carry the EXIF block into the new file.
5. Click a file in the list to compare it, then use the download button on each row or Download all for a ZIP.

JPG Compressor features

What the JPEG quality number actually controls

JPEG splits a photo into 8×8 pixel blocks, converts each block into frequency components with a discrete cosine transform, and divides those components by a quantisation table. Bigger divisors throw away more fine detail, which is where the savings come from. The quality setting simply scales the example tables from the JPEG standard (Annex K): quality 50 uses them as printed, quality 75 halves them, and quality 100 sets every divisor to 1.

Because the tables are stored in the file, the tool can work backwards and estimate the quality an existing photo was saved at. Cameras and editors that use custom tables give an approximate figure, so treat it as a guide. Re-saving at a higher quality never restores lost detail.

Chroma subsampling, baseline and progressive

Our eyes are less sensitive to colour detail than to brightness, so most JPEGs store the two colour channels at half resolution in both directions — written 4:2:0. Thin red text or sharp coloured edges can look slightly fuzzy as a result. In Chrome and Edge the canvas encoder uses 4:2:0 below quality 100 and full-resolution 4:4:4 at 100; the details panel shows the subsampling of both the original and the result, so you always see what your browser wrote.

A baseline JPEG loads from top to bottom, while a progressive one appears blurry first and sharpens in passes; progressive files are often a little smaller for large photos. Browsers can only write baseline JPEGs, so a progressive original becomes baseline here. For screenshots and graphics use the PNG compressor; for smaller photos at similar quality try the WebP compressor.

EXIF metadata: what is removed and what is kept

Phone photos carry an EXIF block with the camera model, date, exposure settings, a preview thumbnail and often the GPS coordinates where the picture was taken. Removing it protects your privacy and typically saves 10–60 KB per photo. XMP and IPTC blocks and comments are removed too. To see what a photo contains before you share it, open it in the EXIF viewer.

When you keep EXIF, the original APP1 segment is copied into the new JPEG. The orientation tag is reset to “normal”, because the browser has already turned the pixels upright, and the stored pixel width and height are updated to the new size. When the original pixels are kept, an upright photo loses all metadata, and a photo that depends on an orientation tag keeps only that tag so it still displays the right way round.